Improvement of the corrosion resistance of amorphous Ni-P coatings modified by a laser–electrodeposition hybrid process: Effect of morphology evolution on the electrochemical corrosion behavior

Abstract

Laser irradiation was applied to a Ni–P electrolyte containing a crystal modifier. This produced a Ni–P alloy surface prepared via electrodeposition that was composed of numerous three-dimensional microcellular structures. The coating maintained its original amorphous structure while reducing the residual tensile stress. This structure replaced the surface crack structure, thus reducing the corrosion rate by nearly a factor of four. The main corrosion mechanism corresponding to the conventional method was stress corrosion, whereas the proposed method involved pitting corrosion. This was primarily because of the formation of corrosion microcells owing to the electrochemical non-uniformity caused by the structures.